Localization of 2',3'-cyclic nucleotide 3'-phosphodiesterase on cultured Schwann cells

Primary cultures of Schwann cells were labeled by indirect immunofluorescence using an antibody directed against 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase). Schwann cells which had been maintained in culture for 8 weeks were labeled with this antibody. Immunoblot analysis of Schwann cell homogenates revealed a single band with a molecular weight of 54,000 daltons which corresponded to a single immunoreactive polypeptide present in myelin prepared from rat sciatic nerve. The subcellular localization of CNPase was examined by fractionation of cultured Schwann cell homogenates with linear sucrose gradients. The distribution of CNPase paralleled that of 5'-nucleotidase, a putative marker for plasma membranes. These results suggest that CNPase is localized on the plasma membranes of Schwann cells and is expressed by the cells in the absence of an axonal stimulus.